Math Skill: Using Parentheses
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Using Parentheses

When evaluating expressions that have parentheses, you always evaluate what is in the parentheses first.
When you don't evaluate what's in the parentheses first, you will get the wrong answer.
Let's take 3 × (8 - 5) as an example.

Right:
 3 × (8 - 5) = 3 × 3 = 9

Evaluate what is in the parentheses first.
Wrong:
 3 × (8 - 5) = 3 × 8 - 5 = 24 - 5 = 19

Ignoring parentheses gets the wrong answer.

If there is a pair of parentheses within a pair of parentheses, then evaluate what is in the inner pair of parentheses first.

Example:

(10 + (6 ÷ 2)) + (4 × 3)

 (10 + (6 ÷ 2)) + (4 × 3) = Evaluate the inner parentheses first (10 + 3) + (4 × 3) = (10 + 3) + (4 × 3) = Evalute the remaining parentheses 13 + 12 = 25

### Complexity=2

 1.   17 + (72 ÷ 8) = 2.   (4 × 1) + 19 =

### Complexity=4

 1.   9(2 × 5) = 2.   16 - (1 × 12) =

### Complexity=6

 1.   (5 + 7) + 8 = 2.   (25 ÷ 5)(18 ÷ 3) =

### Complexity=2

117 + (72 ÷ 8) =
Solution
72/8 => 9
Remove parentheses.
17 + 9 = 26
2(4 × 1) + 19 =
Solution
4 × 1 = 4
Remove parentheses.
4 + 19 = 23

### Complexity=4

19(2 × 5) =
Solution
2 × 5 = 10
Remove parentheses.
9 × 10 = 90
216 - (1 × 12) =
Solution
Remove parentheses.
16 - 12 = 4